Printed circuit board

ABSTRACT

A printed circuit board is provided. The printed circuit board includes an insulating material, and a circuit comprising a first region that partially penetrates the insulating material, and a second region formed on the first region and that protrudes from an upper portion of the insulating material, the first region includes a first electroplating layer and a first electroless plating layer that are formed between the insulating material and the first electroplating layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. 119(a) of KoreanPatent Application No. 10-2018-0148291 filed on Nov. 27, 2018 in theKorean Intellectual Property Office, the entire disclosure of which isincorporated herein by reference for all purposes.

BACKGROUND 1. Field

This disclosure relates to a printed circuit board.

2. Description of Related Art

With the recent miniaturization and the thin form factor of printedcircuit boards, the circuits have become more miniaturized, and it maybe beneficial for microcircuits to closely adhere to insulatingmaterials. Since the sizes of vias are also becoming smaller, it may bebeneficial to utilize technologies other than laser machining, to formthe via holes.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

In a general aspect, a printed circuit board includes an insulatingmaterial, and a circuit comprising a first region that partiallypenetrates the insulating material, and a second region formed on thefirst region and that protrudes from an upper portion of the insulatingmaterial, wherein the first region comprises a first electroplatinglayer and a first electroless plating layer that is formed between theinsulating material and the first electroplating layer.

A width of the first region may be larger than a width of the secondregion.

The second region may include a second electroplating layer formedintegrally with the first electroplating layer on an upper surface ofthe first electroplating layer.

A width of the second electroplating layer may be smaller than a widthof the first electroplating layer.

A width of the first region may be smaller than a width of the secondregion.

The second region may include a second electroplating layer formedintegrally with the first electroplating layer on an upper surface ofthe first electroplating layer, a metal foil disposed along acircumference of a part of an outer portion of the second electroplatinglayer, and formed on an upper surface of the insulating material, and asecond electroless plating layer formed between the secondelectroplating layer and the metal foil, and further formed in anintegral manner with the first electroless plating layer.

A width of the first region may be the same as a width of the secondregion.

The second region may include a second electroplating layer formed in anintegral manner with the first electroplating layer on an upper surfaceof the first electroplating layer, and a second electroless platinglayer disposed along a circumference of a part of an outer portion ofthe second electroplating layer, and formed in an integral manner withthe first electroless plating layer.

A height of the second electroplating layer may be larger than a heightof the second electroless plating layer.

A boundary surface between the first region and the insulating materialmay be a concavely curved surface.

The printed circuit board may further include a first pad formed in alower surface of the insulating material, a via hole formed on the firstpad, and configured to penetrate the insulating material, a via formedin the via hole, and a second pad formed on an upper surface of the via.

A thickness of the via may be larger than a thickness of the firstregion, and a thickness of the second region may be the same as athickness of the second pad.

The first region may be connected to the via, and the second region maybe connected to the second pad.

The via may include a third electroless plating layer formed on an innersurface of the via hole and an upper surface of the first pad, and athird electroplating layer formed on the third electroless platinglayer.

The second pad may include a fourth electroplating layer formed in anintegral manner with the third electroplating layer on an upper surfaceof the third electroplating layer, a metal foil disposed along acircumference of a part of an outer portion of the third electroplatinglayer and further formed on an upper surface of the insulating material,and a fourth electroless plating layer formed between the thirdelectroplating layer and the metal foil and further formed in anintegral manner with the third electroless plating layer.

The via hole may have a concavely curved surface.

The via hole may penetrate an upper portion of the first pad.

In a general aspect, a method of manufacturing a printed circuit boardincludes forming a flexible insulating layer, and forming a circuitcomprising a first region that partially penetrates the flexibleinsulating layer, and a second region formed on the first region andthat protrudes from an upper portion of the flexible insulating layer,wherein the first region comprises a first electroplating layer and afirst electroless plating layer that are formed between the flexibleinsulating layer and the first electroplating layer.

Other features and aspects will be apparent from the following detaileddescription, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A to 3B illustrate a printed circuit board according to anexample;

FIGS. 4A to 5B illustrate a printed circuit board according to anexample;

FIGS. 6A to 7B illustrate a printed circuit board according to anexample;

FIGS. 8 to 15 illustrate a method for manufacturing a printed circuitboard according to an example;

FIGS. 16 to 19 illustrate a method for manufacturing a printed circuitboard according to an example; and

FIGS. 20 to 23 illustrate a method for manufacturing the printed circuitboard according to an example.

Throughout the drawings and the detailed description, unless otherwisedescribed or provided, the same drawing reference numerals will beunderstood to refer to the same elements, features, and structures. Thedrawings may not be to scale, and the relative size, proportions, anddepiction of elements in the drawings may be exaggerated for clarity,illustration, and convenience.

DETAILED DESCRIPTION

The following detailed description is provided to assist the reader ingaining a comprehensive understanding of the methods, apparatuses,and/or systems described herein. However, various changes,modifications, and equivalents of the methods, apparatuses, and/orsystems described herein will be apparent after an understanding of thedisclosure of this application. For example, the sequences of operationsdescribed herein are merely examples, and are not limited to those setforth herein, but may be changed as will be apparent after anunderstanding of the disclosure of this application, with the exceptionof operations necessarily occurring in a certain order. Also,descriptions of features that are known may be omitted for increasedclarity and conciseness.

The features described herein may be embodied in different forms, andare not to be construed as being limited to the examples describedherein. Rather, the examples described herein have been provided merelyto illustrate some of the many possible ways of implementing themethods, apparatuses, and/or systems described herein that will beapparent after an understanding of the disclosure of this application.

Although terms such as “first,” “second,” and “third” may be used hereinto describe various members, components, regions, layers, or sections,these members, components, regions, layers, or sections are not to belimited by these terms. Rather, these terms are only used to distinguishone member, component, region, layer, or section from another member,component, region, layer, or section. Thus, a first member, component,region, layer, or section referred to in examples described herein mayalso be referred to as a second member, component, region, layer, orsection without departing from the teachings of the examples.

The terminology used herein is for describing various examples only, andis not to be used to limit the disclosure. The articles “a,” “an,” and“the” are intended to include the plural forms as well, unless thecontext clearly indicates otherwise. The terms “comprises,” “includes,”and “has” specify the presence of stated features, numbers, operations,members, elements, and/or combinations thereof, but do not preclude thepresence or addition of one or more other features, numbers, operations,members, elements, and/or combinations thereof.

Unless otherwise defined, all terms, including technical and scientificterms, used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure pertains after anunderstanding of the present disclosure. Terms, such as those defined incommonly used dictionaries, are to be interpreted as having a meaningthat is consistent with their meaning in the context of the relevant artand the present disclosure, and are not to be interpreted in anidealized or overly formal sense unless expressly so defined herein.

A term “couple” may not only refer to an example in which respectivecomponents are physically and directly in contact with each other in acontact relationship between the respective components, but may alsorefer to an example in which another component is interposed between therespective components and the respective components are in contact withthe another component.

FIGS. 1 A to 3B illustrate an example of a printed circuit board.

Referring to FIG. 1A, a printed circuit board may include an insulatingmaterial 100 and a circuit 200. The circuit 200 may include a firstregion 210 and a second region 220.

The insulating material 100 insulates circuits on the printed circuitboard from each other. A main component of the insulating material 100may be a resin. However, the main component of the insulating materialis not limited thereto. As the resin of the insulating material 100, athermosetting resin, a thermoplastic resin, or similar resin may beselected. The resin of the insulating material 100 may be an epoxyresin, a polyimide resin, a liquid-crystal polymer (LCP) resin, and thelike. Here, the epoxy resin may be, but not limited to, anaphthalene-based epoxy resin, a bisphenol-A type epoxy resin, abisphenol-F type epoxy resin, a novolac-based epoxy resin, acresol-novolac-based epoxy resin, a rubber-modified epoxy resin, acycloaliphatic epoxy resin, a silicone-based epoxy resin, anitrogen-based epoxy resin, a phosphorus-based epoxy resin, or similarepoxy resins.

The insulating material 100 may contain a fiber reinforcement material110. The fiber reinforcement material 110 contained in the insulatingmaterial 100 may be a glass cloth and may include a glass filament, aglass fiber, a glass fabric, and similar glass-based materials. Thefiber reinforcement material 110 may be positioned at a central portionof the insulating material 100 and may be formed of a plurality offibers so as to have a crumpled cloth form. The insulating material 100including the glass cloth may be a prepreg or an Ajinomoto build-up film(ABF).

The insulating material 100 may contain an inorganic filler, and any oneof silica (SiO₂), barium sulfate (BaSO₄), and alumina (Al₂O₃), or acombination of two or more thereof may be used as the inorganic filler.A material of the inorganic filler may also be, but is not limited to,calcium carbonate, magnesium carbonate, fly ash, natural silica,synthetic silica, kaolin, clay, calcium oxide, magnesium oxide, titaniumoxide, zinc oxide, calcium hydroxide, aluminum hydroxide, magnesiumhydroxide, talc, mica, hydrotalcite, aluminum silicate, magnesiumsilicate, calcium silicate, calcined talc, wollastonite, potassiumtitanate, magnesium sulfate, calcium sulfate, magnesium phosphate, orthe like.

A thickness of the insulating material 100 may be 100 μm or less, but isnot limited thereto.

Meanwhile, FIG. 1A also illustrates an insulating layer 100′ stackedbeneath the insulating material 100. The insulating layer 100′ may bethe same layer as the insulating material 100. In addition, theinsulating layer 100′ may be formed of a material different from thematerial of the insulating material 100, and may be a core layer, anouter layer (solder resist layer), or the like.

The circuit 200 is a path for transmitting an electric signal and isformed of a conductive material. The first region 210 of the circuit 200may be embedded in the insulating material 100 while partiallypenetrating through the insulating material 100. The second region 220of the circuit 200 may be formed on the first region 210, and mayprotrude from an upper portion of the insulating material 100. That is,the circuit 200 mat have a structure in which the circuit 200 issemi-embedded in the insulating material 100. The circuit 200 may beformed by blasting, and a depth at which the circuit 200 is embedded maybe adjusted depending on a condition of the blasting.

In the example, a width of the first region 210 may be larger than awidth of the second region 220. FIG. 1B illustrates the first region 210and the second region 220 of the circuit 200.

The first region 210 may include a first electroplating layer P1 and afirst electroless plating layer S1.

The first electroplating layer P1 occupies the majority of the firstregion 210 of the circuit 200, and may be a metal plating layer formedin the insulating material 100 by an electroplating method. The firstelectroplating layer P1 may be formed of metal such as copper (Cu),silver (Ag), palladium (Pd), aluminum (Al), nickel (Ni), titanium (Ti),gold (Au), platinum (Pt), or the like, or an alloy thereof, but is notlimited thereto.

The first electroless plating layer S1 may be formed in the insulatingmaterial 100. Specifically, the first electroless plating layer S1 maybe formed entirely between the insulating material 100 and the firstelectroplating layer P1, and may be a metal plating layer that is formedby an electroless plating method. The first electroplating layer P1 maybe grown from the first electroless plating layer S1. Therefore, asillustrated in FIG. 1B, the first electroless plating layer S1 may beformed to surround side surfaces and a lower surface of the firstelectroplating layer P1, except for an upper surface of the firstelectroplating layer P1.

The first electroless plating layer S1 may be formed of metal such ascopper (Cu), silver (Ag), palladium (Pd), aluminum (Al), nickel (Ni),titanium (Ti), gold (Au), platinum (Pt), or the like, or an alloythereof. The first electroless plating layer S1 may be formed of thesame metal as that of the first electroplating layer P1.

A thickness of the first electroless plating layer S1 may be smallerthan a thickness of the first electroplating layer P1, and may be 5 μmor less.

The second region 220 may include a second electroplating layer P2.

The second electroplating layer P2 may be formed integrally with thefirst electroplating layer P1 on the upper surface of the firstelectroplating layer P1. The second electroplating layer P2 may be thefirst electroplating layer P1 extended in an upward direction. Thesecond electroplating layer P2 may be formed of metal such as copper(Cu), silver (Ag), palladium (Pd), aluminum (Al), nickel (Ni), titanium(Ti), gold (Au), platinum (Pt), or the like, or an alloy thereof, but isnot limited thereto, and may be formed of the same metal as the materialof the first electroplating layer P1.

A width of the second electroplating layer P2 may be smaller than awidth of the first electroplating layer P1. A horizontal cross-sectionalarea of the second electroplating layer P2 may be smaller than ahorizontal cross-sectional area of the first electroplating layer P1.Therefore, the upper surface of the first electroplating layer P1 may beexposed through an upper surface of the insulating material 100.

As described above, the width of the first region 210 may be larger thanthe width of the second region 220. Referring to FIG. 2A, a width A1 ofthe first region 210 refers to a width of a region including both of thefirst electroplating layer P1 and the first electroless plating layerS1, and a width B1 of the second region 220 refers to a width of thesecond electroplating layer P2.

In an example where the first region 210 of the circuit 200 is disposedin the insulating material 100, a contact area between the circuit 200and the insulating material 100 may be large, which results in anexcellent close adhesion between the circuit 200 and the insulatingmaterial 100. Further, in an example where the width of the first region210 is larger than the width of the second region 220, since a width ofthe circuit 200 is determined depending on the width of the secondregion 220, a circuit width of the printed circuit board is decreasedand a contact area between the circuit 200 and the insulating material100 may be secured by the first region 210.

Meanwhile, as illustrated in FIG. 2B, a boundary surface between thefirst region 210 and the insulating material 100 may be a concavelycurved surface (U-letter-shaped curved surface). A curved shape of theboundary surface between the first region 210 and the insulatingmaterial 100 may be changed as necessary, and may be adjusted dependingon a condition of the blasting.

Referring back to FIG. 1A, the printed circuit board according to anexample may further include a first pad 300, a via hole VH, a via 400,and a second pad 500.

The first pad 300 may be formed in a lower surface of the insulatingmaterial 100 and may be embedded in the lower surface of the insulatingmaterial 100 such that, except for the lower surface of the first pad300, side surfaces and an upper surface of the first pad 300 may be incontact with the insulating material 100. The first pad 300 may beprovided on an end portion of a circuit formed in the lower surface ofthe insulating material 100.

The first pad 300 may be formed of metal such as copper (Cu), silver(Ag), palladium (Pd), aluminum (Al), nickel (Ni), titanium (Ti), gold(Au), platinum (Pt), or the like, or an alloy thereof, and may beconstituted by a plurality of layers formed of a homogeneous metal orheterogeneous metals.

The via hole VH penetrates through the insulating material 100 to beformed on the first pad 300. A horizontal cross-sectional area of thevia hole VH may be decreased as the via hole penetrates toward a lowerportion of the insulating material 100. Further, although notillustrated in FIG. 1A, an inner surface of the via hole VH may be aconcavely curved (U-letter shape) surface (see FIG. 10B). In addition,the via hole VH may partially penetrate through an upper portion of thefirst pad 300 and an upper surface of the first pad 300 may include aconcavely (U-letter shape) curved surface (see FIG. 10B).

The via 400 may be formed of a conductive material and may be formed inthe via hole VH. The via 400 may electrically connect circuits indifferent layers to each other. The via 400 electrically connects thefirst and second pads 300 and 500 to each other.

The via 400 includes a third electroless plating layer S3 and a thirdelectroplating layer P3. The via 400 may have the same layer structureas that of the first region 210 of the circuit 200.

The third electroless plating layer S3 may be a metal plating layerformed on the inner surface of the via hole VH and a bottom surface (theupper surface of the first pad 300) of the via hole VH. The thirdelectroplating layer P3 may be a metal plating layer grown from thethird electroless plating layer S3 and may be formed on the thirdelectroless plating layer S3 and fills the via hole VH. The thirdelectroless plating layer S3 may be formed at the same thickness as thethickness of the first electroless plating layer S1 of the first region210 of the circuit 200, and the third electroplating layer P3 may beformed to be thicker than the third electroless plating layer S3.

Meanwhile, each of the third electroless plating layer S3 and the thirdelectroplating layer P3 may be formed of metal such as copper (Cu),silver (Ag), palladium (Pd), aluminum (Al), nickel (Ni), titanium (Ti),gold (Au), platinum (Pt), or the like, or an alloy thereof, but is notlimited thereto.

The second pad 500 may be formed on an upper surface of the via 400 andmay be connected to an end portion of the circuit 200 as illustrated inFIG. 3A.

The second pad 500 may include a metal foil M2, a fourth electrolessplating layer S4, and a fourth electroplating layer P4.

The metal foil M2 may be formed on the upper surface of the insulatingmaterial 100, and may be formed in a ring shape (for example, an openedring shape (C-letter shape)) along a circumference of the upper surfaceof the via 400. The metal foil M2 may be formed of metal such as copper(Cu), silver (Ag), palladium (Pd), aluminum (Al), nickel (Ni), titanium(Ti), gold (Au), platinum (Pt), or the like, or an alloy thereof, but isnot limited thereto.

The fourth electroless plating layer S4 may be formed on an uppersurface and an inner surface of the metal foil M2, and may be formedintegrally with the third electroless plating layer S3 of the via 400. Aside surface of the fourth electroless plating layer S4 may be exposedthrough a side surface of the second pad 500.

The fourth electroplating layer P4 may be a metal plating layer grownfrom the fourth electroless plating layer S4 and may be formedintegrally with the third electroplating layer P3 on the upper surfaceof the third electroplating layer P3 of the via 400. The fourthelectroplating layer P4 may also be formed on the fourth electrolessplating layer S4 disposed on the upper surface of the metal foil M2. Inthis example, the metal foil M2 may be formed along a circumference of apart of an outer portion of the fourth electroplating layer P4, and thefourth electroless plating layer S4 may be interposed between the metalfoil M2 and the fourth electroplating layer P4.

A height of the second pad 500 may be determined depending on athickness of each of the metal foil M2, the fourth electroless platinglayer S4, and the fourth electroplating layer P4, and may be the same asa height of the second region 220 of the circuit 200.

Referring to FIGS. 3A and 3B, in an example where the second pad 500 isprovided on an end portion of the circuit 200, the third electrolessplating layer S3 of the via 400 may be connected to the firstelectroless plating layer 51 of the circuit 200. Here, the thirdelectroless plating layer S3 of the via 400 and the first electrolessplating layer 51 of the circuit 200 may be formed integrally with eachother.

The third electroplating layer P3 of the via 400 and the firstelectroplating layer P1 of the circuit 200 may be connected to eachother and may be formed integrally with each other. Further, the fourthelectroplating layer P4 of the second pad 500 and the secondelectroplating layer P2 of the circuit 200 may be connected to eachother and formed integrally with each other.

FIGS. 4A to 5B illustrate a printed circuit board according to anexample.

Referring to FIG. 4A, a printed circuit board according to an exampleincludes an insulating material 100 and a circuit 200. The circuit 200may include a first region 210 and a second region 220.

The insulating material 100 insulates circuits on the printed circuitboard from each other. A main component of the insulating material 100may be a resin. However, the main component of the insulating material100 is not limited thereto. As the resin of the insulating material 100,a thermosetting resin, a thermoplastic resin, or the like may beselected. The resin of the insulating material 100 may be an epoxyresin, a polyimide resin, a liquid-crystal polymer (LCP) resin, and thelike. Here, the epoxy resin may be, but not limited to, anaphthalene-based epoxy resin, a bisphenol-A type epoxy resin, abisphenol-F type epoxy resin, a novolac-based epoxy resin, acresol-novolac-based epoxy resin, a rubber-modified epoxy resin, acycloaliphatic epoxy resin, a silicone-based epoxy resin, anitrogen-based epoxy resin, a phosphorus-based epoxy resin, or similarepoxy resin.

The insulating material 100 may contain a fiber reinforcement material110. The fiber reinforcement material 110 contained in the insulatingmaterial 100 may be a glass cloth and may include a glass filament, aglass fiber, a glass fabric, and similar glass-based materials. Thefiber reinforcement material 110 may be positioned at a central portionof the insulating material 100 and may be formed of a plurality offibers so as to have a crumpled cloth form. The insulating material 100including the glass cloth may be a prepreg or an Ajinomoto build-up film(ABF).

The insulating material 100 may contain an inorganic filler, and any oneof silica (SiO₂), barium sulfate (BaSO₄), and alumina (Al₂O₃), or acombination of two or more thereof may be used as the inorganic filler.A material of the inorganic filler may also be, but not limited to,calcium carbonate, magnesium carbonate, fly ash, natural silica,synthetic silica, kaolin, clay, calcium oxide, magnesium oxide, titaniumoxide, zinc oxide, calcium hydroxide, aluminum hydroxide, magnesiumhydroxide, talc, mica, hydrotalcite, aluminum silicate, magnesiumsilicate, calcium silicate, calcined talc, wollastonite, potassiumtitanate, magnesium sulfate, calcium sulfate, magnesium phosphate, orthe like.

A thickness of the insulating material 100 may be 100 μm or less, but isnot limited thereto. The thickness of the insulating material may begreater than 100 μm.

Meanwhile, FIG. 4A also illustrates an insulating layer 100′ stackedbeneath the insulating material 100. The insulating layer 100′ may bethe same layer as the insulating material 100. In addition, theinsulating layer 100′ may be formed of a material different from amaterial of the insulating material 100, and may be a core layer, anouter layer (solder resist layer), or the like.

The circuit 200 is a path for transmitting an electric signal and isformed of a conductive material. The first region 210 of the circuit 200may be embedded in the insulating material 100 while partiallypenetrating through a portion of the insulating material 100. The secondregion 220 of the circuit 200 may be formed on the first region 210 andprotrudes from an upper portion of the insulating material 100. That is,the circuit 200 has a structure in which the circuit 200 is partiallyembedded in the insulating material 100. The circuit 200 may be formedby blasting, and a depth at which the circuit 200 is embedded may beadjusted depending on a condition of the blasting.

In the example, a width of the first region 210 may be smaller than awidth of the second region 220. FIG. 4B illustrates the first region 210and the second region 220 of the circuit 200.

The first region 210 includes a first electroplating layer P1 and afirst electroless plating layer S1.

The first electroplating layer P1 occupies the majority of the firstregion 210 of the circuit 200, and may be a metal plating layer formedin the insulating material 100 by an electroplating method. The firstelectroplating layer P1 may be formed of metal such as copper (Cu),silver (Ag), palladium (Pd), aluminum (Al), nickel (Ni), titanium (Ti),gold (Au), platinum (Pt), or the like, or an alloy thereof, but is notlimited thereto.

The first electroless plating layer S1 may be formed in the insulatingmaterial 100. Specifically, first electroless plating layer S1 may beformed entirely between the insulating material 100 and the firstelectroplating layer P1, and may be a metal plating layer formed by anelectroless plating method. The first electroplating layer P1 may begrown from the first electroless plating layer S1. Therefore, asillustrated in FIG. 4B, the first electroless plating layer S1 may beformed to surround side surfaces and a lower surface of the firstelectroplating layer P1, except for an upper surface of the firstelectroplating layer P1.

The first electroless plating layer S1 may be formed of metal such ascopper (Cu), silver (Ag), palladium (Pd), aluminum (Al), nickel (Ni),titanium (Ti), gold (Au), platinum (Pt), or the like, or an alloythereof, but is not limited thereto. The first electroless plating layerS1 may be formed of the same metal as that of the first electroplatinglayer P1.

A thickness of the first electroless plating layer S1 may be smallerthan a thickness of the first electroplating layer P1, and may be 5 μmor less.

The second region 220 may include a metal foil M1, a second electrolessplating layer S2, and a second electroplating layer P2.

The metal foil M1 may be formed on an upper surface of the insulatingmaterial 100 and may be formed in a ring shape along a circumference ofan upper surface of the first region 210 of the circuit 200. The metalfoil M1 may be formed of metal such as copper (Cu), silver (Ag),palladium (Pd), aluminum (Al), nickel (Ni), titanium (Ti), gold (Au),platinum (Pt), or the like, or an alloy thereof, but is not limitedthereto.

The second electroless plating layer S2 may be formed on an uppersurface and an inner surface of the metal foil M1, and may be formedintegrally with the first electroless plating layer S1 of the firstregion 210 of the circuit 200.

The second electroplating layer P2 may be a metal plating layer grownfrom the second electroless plating layer S2 and is formed integrallywith the first electroplating layer P1 on the upper surface of the firstelectroplating layer P1 of the first region 210 of the circuit 200. Thesecond electroplating layer P2 is also formed on the second electrolessplating layer S2 disposed on the upper surface of the metal foil M1. Inthis example, the metal foil M1 may be formed along a circumference of apart of an outer portion of the second electroplating layer P2, and thesecond electroless plating layer S2 may be interposed between the metalfoil M1 and the second electroplating layer P2.

The second electroplating layer P2 may be formed of metal such as copper(Cu), silver (Ag), palladium (Pd), aluminum (Al), nickel (Ni), titanium(Ti), gold (Au), platinum (Pt), or the like, or an alloy thereof, but isnot limited thereto. The second electroplating layer P2 may be formed ofthe same metal as the material of the first electroplating layer P1.

As described above, the width of the first region 210 may be smallerthan the width of the second region 220. Referring to FIG. 5A, a widthA2 of the first region 210 may refer to a width of a region includingboth of the first electroplating layer P1 and the first electrolessplating layer S1, and a width B2 of the second region 220 means a widthof a region including all of the metal foil M1, the secondelectroplating layer P2, and the second electroless plating layer S2. Itshould be noted that the width B2 of the second region 220 may be thesame as a width of the second electroplating layer P2.

In an example where the first region 210 of the circuit 200 is disposedin the insulating material 100, a contact area between the circuit 200and the insulating material 100 may be large, which results in anexcellent close adhesion between the circuit 200 and the insulatingmaterial 100. Further, in an example where the second region 220 islarger than the first region 210, a size of an upper surface of thesecond region 220 may be sufficiently secured. For example, in anexample where at least a portion of the circuit 200 functions as aconnection pad, it is preferable that the size of the upper surface ofthe second region 220 is sufficiently secured in terms of connectionreliability.

Meanwhile, as illustrated in FIG. 5B, a boundary surface between thefirst region 210 and the insulating material 100 may be a concavelycurved surface (U-letter-shaped curved surface). A curved shape of theboundary surface between the first region 210 and the insulatingmaterial 100 may be changed as necessary, and may be adjusted dependingon a condition of the blasting.

Referring back to FIG. 4A, the printed circuit board according to theexample may further include a first pad 300, a via hole VH, a via 400,and a second pad 500.

The first pad 300 may be formed in a lower surface of the insulatingmaterial 100 and may be embedded in the lower surface of the insulatingmaterial 100 such that, except for the lower surface of the first pad300, side surfaces and an upper surface of the first pad 300 may be incontact with the insulating material 100. The first pad 300 may beprovided on an end portion of a circuit formed in the lower surface ofthe insulating material 100.

The first pad 300 may be formed of metal such as copper (Cu), silver(Ag), palladium (Pd), aluminum (Al), nickel (Ni), titanium (Ti), gold(Au), platinum (Pt), or the like, or an alloy thereof, but is notlimited thereto. The first pad 300 may be constituted by a plurality oflayers formed of a homogeneous metal or heterogeneous metals.

The via hole VH penetrates through the insulating material 100 to beformed on the first pad 300. A horizontal cross-sectional area of thevia hole VH may be decreased toward a lower portion of the insulatingmaterial 100. Further, although not illustrated in FIG. 4A, an innersurface of the via hole VH may be a concavely curved (U-letter shape)surface (see FIG. 10B). In addition, the via hole VH may partiallypenetrate through an upper portion of the first pad 300 and the uppersurface of the first pad 300 may include a concavely (U-letter shape)curved surface (see FIG. 10B).

The via 400 is formed of a conductive material and formed in the viahole VH and electrically connects circuits in different layers to eachother. The via 400 electrically connects the first and second pads 300and 500 to each other.

The via 400 includes a third electroless plating layer S3 and a thirdelectroplating layer P3. The via 400 may have the same layer structureas the layer structure of the first region 210 of the circuit 200.

The third electroless plating layer S3 is a metal plating layer formedon the inner surface of the via hole VH and a bottom surface (the uppersurface of the first pad 300) of the via hole VH. The thirdelectroplating layer P3 is a metal plating layer grown from the thirdelectroless plating layer S3 and is formed on the third electrolessplating layer S3 and fills the via hole VH. The third electrolessplating layer S3 may be formed at the same thickness as that of thefirst electroless plating layer S1 of the first region 210 of thecircuit 200, and the third electroplating layer P3 may be formed to bethicker than the third electroless plating layer S3.

Meanwhile, each of the third electroless plating layer S3 and the thirdelectroplating layer P3 may be formed of metal such as copper (Cu),silver (Ag), palladium (Pd), aluminum (Al), nickel (Ni), titanium (Ti),gold (Au), platinum (Pt), or the like, or an alloy thereof.

The second pad 500 is formed on an upper surface of the via 400 and maybe connected to an end portion of the circuit 200.

The second pad 500 may include a metal foil M2, a fourth electrolessplating layer S4, and a fourth electroplating layer P4. The second pad500 may have the same layer structure as the layer structure of thesecond region 220 of the circuit 200.

The metal foil M2 may be formed on the upper surface of the insulatingmaterial 100, and may be formed in a ring shape (particularly, the metalfoil M1 and the metal foil M2 may be integrally formed in a closed ringshape (O-letter shape)) along a circumference of the upper surface ofthe via 400. The metal foil M2 may be formed of metal such as copper(Cu), silver (Ag), palladium (Pd), aluminum (Al), nickel (Ni), titanium(Ti), gold (Au), platinum (Pt), or the like, or an alloy thereof.

The fourth electroless plating layer S4 may be formed on an uppersurface and an inner surface of the metal foil M2, and may be formedintegrally with the third electroless plating layer S3 of the via 400. Aside surface of the fourth electroless plating layer S4 is exposedthrough a side surface of the second pad 500.

The fourth electroplating layer P4 is a metal plating layer grown fromthe fourth electroless plating layer S4 and is formed integrally withthe third electroplating layer P3 on the upper surface of the thirdelectroplating layer P3 of the via 400. The fourth electroplating layerP4 is also formed on the fourth electroless plating layer S4 disposed onthe upper surface of the metal foil M2. In this example, the metal foilM2 may be formed along a circumference of a part of an outer portion ofthe fourth electroplating layer P4, and the fourth electroless platinglayer S4 may be interposed between the metal foil M2 and the fourthelectroplating layer P4.

A height of the second pad 500 may be determined depending on athickness of each of the metal foil M2, the fourth electroless platinglayer S4, and the fourth electroplating layer P4, and may be the same asa height of the second region 220 of the circuit 200.

In an example where the second pad 500 is provided on an end portion ofthe circuit 200, the third electroless plating layer S3 of the via 400may be connected to the first electroless plating layer S1 of thecircuit 200. The fourth electroless plating layer S4 of the second pad500 may be connected to the second electroless plating layer S2 of thecircuit 200. Here, the third electroless plating layer S3 of the via 400and the first electroless plating layer S1 of the circuit 200 are formedintegrally with each other, and the fourth electroless plating layer S4and the second electroless plating layer S2 may be formed integrallywith each other.

Further, the third electroplating layer P3 of the via 400 and the firstelectroplating layer P1 of the circuit 200 may be connected to eachother and formed integrally with each other. The fourth electroplatinglayer P4 of the second pad 500 and the second electroplating layer P2 ofthe circuit 200 may be connected to each other and formed integrallywith each other. In addition, the metal foil M2 of the second pad 500may be connected to the metal foil M1 of the circuit 200.

FIGS. 6A to 7B illustrate a printed circuit board according to anexample.

Referring to FIG. 6A, a printed circuit board according to an exampleincludes an insulating material 100 and a circuit 200. The circuit 200may include a first region 210 and a second region 220.

The insulating material 100 insulates circuits on the printed circuitboard from each other. A main component of the insulating material 100may be a resin. However, the main component of the insulating material100 is not limited thereto. As the resin of the insulating material 100,a thermosetting resin, a thermoplastic resin, or the like may beselected. The resin of the insulating material 100 may be an epoxyresin, a polyimide resin, a liquid-crystal polymer (LCP) resin, and thelike. Here, the epoxy resin may be, but not limited to, anaphthalene-based epoxy resin, a bisphenol-A type epoxy resin, abisphenol-F type epoxy resin, a novolac-based epoxy resin, acresol-novolac-based epoxy resin, a rubber-modified epoxy resin, acycloaliphatic epoxy resin, a silicone-based epoxy resin, anitrogen-based epoxy resin, a phosphorus-based epoxy resin, or similarresins.

The insulating material 100 may contain a fiber reinforcement material110. The fiber reinforcement material 110 contained in the insulatingmaterial 100 may be a glass cloth and may include a glass filament, aglass fiber, a glass fabric, and similar glass-based materials. Thefiber reinforcement material 110 may be positioned at a central portionof the insulating material 100 and formed of a plurality of fibers so asto have a crumpled cloth form. The insulating material 100 including theglass cloth may be a prepreg or an Ajinomoto build-up film (ABF).

The insulating material 100 may contain an inorganic filler, and any oneof silica (SiO₂), barium sulfate (BaSO₄), and alumina (Al₂O₃), or acombination of two or more thereof may be used as the inorganic filler.A material of the inorganic filler may also be, but not limited to,calcium carbonate, magnesium carbonate, fly ash, natural silica,synthetic silica, kaolin, clay, calcium oxide, magnesium oxide, titaniumoxide, zinc oxide, calcium hydroxide, aluminum hydroxide, magnesiumhydroxide, talc, mica, hydrotalcite, aluminum silicate, magnesiumsilicate, calcium silicate, calcined talc, wollastonite, potassiumtitanate, magnesium sulfate, calcium sulfate, magnesium phosphate, orthe like.

A thickness of the insulating material 100 may be 100 μm or less, but isnot limited thereto. A thickness of the insulating material 100 may begreater than 100 μm.

Meanwhile, FIG. 6A also illustrates an insulating layer 100′ stackedbeneath the insulating material 100, and the insulating layer 100′ maybe the same layer as the insulating material 100. In addition, theinsulating layer 100′ may be formed of a material different from amaterial of the insulating material 100, and may be a core layer, anouter layer (solder resist layer), or the like.

The circuit 200 is a path for transmitting an electric signal and isformed of a conductive material. The first region 210 of the circuit 200is embedded in the insulating material 100 while partially penetratingthrough the insulating material 100 and the second region 220 of thecircuit 200 may be formed on the first region 210, and protrudes from anupper portion of the insulating material 100. That is, the circuit 200has a structure in which the circuit 200 is partially embedded in theinsulating material 100. The circuit 200 may be formed by blasting, anda depth at which the circuit 200 is embedded may be adjusted dependingon a condition of the blasting.

In the example, a width of the first region 210 may be the same as awidth of the second region 220. FIG. 6B illustrates the first region 210and the second region 220 of the circuit 200.

The first region 210 includes a first electroplating layer P1 and afirst electroless plating layer S1.

The first electroplating layer P1 occupies the majority of the firstregion 210 of the circuit 200, and is a metal plating layer formed inthe insulating material 100 by an electroplating method. The firstelectroplating layer P1 may be formed of metal such as copper (Cu),silver (Ag), palladium (Pd), aluminum (Al), nickel (Ni), titanium (Ti),gold (Au), platinum (Pt), or the like, or an alloy thereof.

The first electroless plating layer S1 is formed in the insulatingmaterial 100, specifically, is formed entirely between the insulatingmaterial 100 and the first electroplating layer P1, and is a metalplating layer formed by an electroless plating method. The firstelectroplating layer P1 is grown from the first electroless platinglayer S1. Therefore, as illustrated in FIG. 1B, the first electrolessplating layer S1 may be formed to surround side surfaces and a lowersurface of the first electroplating layer P1, except for an uppersurface of the first electroplating layer P1.

The first electroless plating layer S1 may be formed of metal such ascopper (Cu), silver (Ag), palladium (Pd), aluminum (Al), nickel (Ni),titanium (Ti), gold (Au), platinum (Pt), or the like, or an alloythereof, but is not limited thereto. The first electroless plating layerS1 may be formed of the same metal as that of the first electroplatinglayer P1.

A thickness of the first electroless plating layer S1 may be smallerthan a thickness of the first electroplating layer P1, and may be 5 μmor less.

The second region 220 may include a second electroless plating layer S2and a second electroplating layer P2.

The second electroless plating layer S2 may be formed in a ring shape onan edge of an upper surface of the first region 210 of the circuit 200,and may be formed integrally with the first electroless plating layer S1on the first electroless plating layer S1 of the first region 210 of thecircuit 200. The second electroless plating layer S2 may be formed ofthe same metal as that of the first electroless plating layer S1.

The second electroplating layer P2 may be a metal plating layer grownfrom the second electroless plating layer S2 and may be formed on aninner side and an upper surface of the second electroless plating layerS2. In this example, the second electroless plating layer S2 may beformed along a circumference of a part of an outer portion of the secondelectroplating layer P2 and a height of the second electroless platinglayer S2 may be smaller than a height of the second region 220. Thesecond electroplating layer P2 may be formed integrally with the firstelectroplating layer P1 on the upper surface of the first electroplatinglayer P1 of the first region 210 of the circuit 200.

The second electroless plating layer S2 and the second electroplatinglayer P2 may be formed of metal such as copper (Cu), silver (Ag),palladium (Pd), aluminum (Al), nickel (Ni), titanium (Ti), gold (Au),platinum (Pt), or the like, or an alloy thereof, but are not limitedthereto. The second electroless plating layer S2 and the secondelectroplating layer P2 may be formed of the same metal as the materialof the first electroless plating layer S1 and the first electroplatinglayer P1.

As described above, the width of the first region 210 may be the same asthe width of the second region 220. Referring to FIG. 7A, a width A3 ofthe first region 210 may refer to a width of a region including both ofthe first electroplating layer P1 and the first electroless platinglayer S1, and a width B3 of the second region 220 may refer to a widthof a region including both of the second electroplating layer P2 and thesecond electroless plating layer S2. It should be noted that the widthB3 of the second region 220 may be the same as a width of the secondelectroplating layer P2.

In the example where the first region 210 of the circuit 200 is disposedin the insulating material 100, a contact area between the circuit 200and the insulating material 100 may be large, which results in anexcellent close adhesion between the circuit 200 and the insulatingmaterial 100. When it is necessary that the circuit 200 is formed at auniform width in a vertical direction, the width of the first region 210and the width of the second region 220 of the circuit 200 may be thesame as each other.

Meanwhile, as illustrated in FIG. 7B, a boundary surface between thefirst region 210 and the insulating material 100 may be a concavelycurved surface (U-letter-shaped curved surface). A curved shape of theboundary surface between the first region 210 and the insulatingmaterial 100 may be changed as necessary, and may be adjusted dependingon a condition of the blasting.

Referring back to FIG. 6A, the printed circuit board according to theexample may further include a first pad 300, a via hole VH, a via 400,and a second pad 500.

The first pad 300 may be formed in a lower surface of the insulatingmaterial 100 and may be embedded in the lower surface of the insulatingmaterial 100 such that, except for the lower surface of the first pad300, side surfaces and an upper surface of the first pad 300 may be incontact with the insulating material 100. The first pad 300 may beprovided on an end portion of a circuit formed in the lower surface ofthe insulating material 100.

The first pad 300 may be formed of metal such as copper (Cu), silver(Ag), palladium (Pd), aluminum (Al), nickel (Ni), titanium (Ti), gold(Au), platinum (Pt), or the like, or an alloy thereof, and may beconstituted by a plurality of layers formed of a homogeneous metal orheterogeneous metals.

The via hole VH penetrates through the insulating material 100 to beformed on the first pad 300. A horizontal cross-sectional area of thevia hole VH may be formed in a tapered manner toward a lower portion ofthe insulating material 100. Further, although not illustrated in FIG.6A, an inner surface of the via hole VH may be a concavely curved(U-letter shape) surface (see FIG. 10B). In addition, the via hole VHmay partially penetrate through an upper portion of the first pad 300and the upper surface of the first pad 300 may include a concavely(U-letter shape) curved surface (see FIG. 10B).

The via 400 is formed of a conductive material and formed in the viahole VH. The via 400 may electrically connect circuits in differentlayers to each other. The via 400 electrically connects the first andsecond pads 300 and 500 to each other.

The via 400 includes a third electroless plating layer S3 and a thirdelectroplating layer P3. The via 400 may have the same layer structureas the layer structure of the first region 210 of the circuit 200.

The third electroless plating layer S3 is a metal plating layer formedon the inner surface of the via hole VH and a bottom surface (the uppersurface of the first pad 300) of the via hole VH. The thirdelectroplating layer P3 is a metal plating layer grown from the thirdelectroless plating layer S3 and is formed on the third electrolessplating layer S3 and fills the via hole VH. The third electrolessplating layer S3 may be formed at the same thickness as that of thefirst electroless plating layer S1 of the first region 210 of thecircuit 200, and the third electroplating layer P3 may be formed to bethicker than the third electroless plating layer S3.

Meanwhile, each of the third electroless plating layer S3 and the thirdelectroplating layer P3 may be formed of metal such as copper (Cu),silver (Ag), palladium (Pd), aluminum (Al), nickel (Ni), titanium (Ti),gold (Au), platinum (Pt), or the like, or an alloy thereof, but is notlimited thereto.

The second pad 500 may be formed on an upper surface of the via 400 andmay be connected to an end portion of the circuit 200.

The second pad 500 may include a metal foil M2, a fourth electrolessplating layer S4, and a fourth electroplating layer P4.

The metal foil M2 may be formed on the upper surface of the insulatingmaterial 100, and may be formed in a ring shape (for example, an openedring shape (C-letter shape)) along a circumference of the upper surfaceof the via 400. The metal foil M2 may be formed of metal such as copper(Cu), silver (Ag), palladium (Pd), aluminum (Al), nickel (Ni), titanium(Ti), gold (Au), platinum (Pt), or the like, or an alloy thereof.

The fourth electroless plating layer S4 may be formed on an uppersurface and an inner surface of the metal foil M2, and may be formedintegrally with the third electroless plating layer S3 of the via 400.(See FIG. 11). A side surface of the fourth electroless plating layer S4may be exposed through a side surface of the second pad 500.

The fourth electroplating layer P4 is a metal plating layer grown fromthe fourth electroless plating layer S4, and may be formed integrallywith the third electroplating layer P3 on the upper surface of the thirdelectroplating layer P3 of the via 400. The fourth electroplating layerP4 may also be formed on the fourth electroless plating layer S4disposed on the upper surface of the metal foil M2. In this example, themetal foil M2 may be formed along a circumference of a part of an outerportion of the fourth electroplating layer P4, and the fourthelectroless plating layer S4 is interposed between the metal foil M2 andthe fourth electroplating layer P4.

A height of the second pad 500 may be determined depending on athickness of each of the metal foil M2, the fourth electroless platinglayer S4, and the fourth electroplating layer P4, and may be the same asa height of the second region 220 of the circuit 200.

In an example where the second pad 500 is provided on an end portion ofthe circuit 200, the third electroless plating layer S3 of the via 400may be connected to the first electroless plating layer S1 of thecircuit 200. The fourth electroless plating layer S4 of the second pad500 may be connected to the second electroless plating layer S2 of thecircuit 200. Here, the third electroless plating layer S3 of the via 400and the first electroless plating layer S1 of the circuit 200 may beformed integrally with each other, and the fourth electroless platinglayer S4 and the second electroless plating layer S2 may be formedintegrally with each other.

Further, the third electroplating layer P3 of the via 400 and the firstelectroplating layer P1 of the circuit 200 may be connected to eachother and formed integrally with each other. The fourth electroplatinglayer P4 of the second pad 500 and the second electroplating layer P2 ofthe circuit 200 may be connected to each other and formed integrallywith each other.

Hereinafter, a method for manufacturing a printed circuit board will bedescribed.

FIGS. 8 to 15 illustrate a method for manufacturing the printed circuitboard according to an example.

Referring to FIG. 8, a first pad 300 is formed on an insulating layer100′, and an insulating material 100 that covers the first pad 300 isformed. A metal foil M may be stacked on the insulating material 100. Aresist R is stacked on the metal foil M and is patterned. A thickness ofthe resist R may be 50 μm or more, but is not limited thereto. Thepatterned resist R may include openings with different depths. That is,a shallow opening R1 may partially, (not fully), penetrate through theresist R, and a deep opening R2 that fully penetrates through the resistR may each be provided in the resist R. A width of the shallow openingR1 may be smaller than a width of the deep opening R2. The shallowopening R1 may correspond to a portion of the circuit board at which acircuit 200 is to be formed, and the deep opening R2 may correspond to aportion of the circuit board at which a via 400 is to be formed.

The resist R may be photosensitive, and the opening of the resist R maybe machined by exposure and development. An opening machining resolutionmay vary depending on a thickness of the resist R, and in an examplewhere a pitch of openings is small with respect to the resolution, theopenings may be the shallow openings R1 due to residues of the resist R.For example, in an example where the thickness of the resist R is 50 μm,the opening machining resolution (that is, a minimum pitch at which twoopenings may be machined so that the two openings may be distinguishedfrom each other) may be 40 μm, and in an example where a pitch of twoopenings to be machined is 30 μm, the openings may be the shallowopenings R1 due to residues of the resist R generated at a lower side ofthe openings.

Referring to FIG. 9, the insulating material 100 and the metal foil Mare subjected to the blasting operation in a state in which thepatterned resist R is formed. The metal foil M and the insulatingmaterial 100 may be simultaneously machined by the blasting process toform a circuit hole H and a via hole VH.

The blasting process may be sandblasting. The sandblasting is a methodof propelling abrasives (AB, micro powder) against a substrate forphysical machining. As the abrasives, at least one of alumina (Al₂O₃)and silicon carbide (SiC) may be used. A nozzle from which the abrasivesAB are sprayed may be divided into two types including a slit nozzle anda circular nozzle, and may be selected depending on physical propertiesof the insulating material 100 and the metal foil M. In addition, amachine for the blasting process may be divided into a suction typemachine and direct pressure type machine, and may be selected dependingon shapes of the circuit hole H and the via hole VH.

Since the metal foil M and the insulating material 100, which areheterogeneous materials, may be simultaneously machined by the blastingprocess, there is no need to remove the metal foil M in advance beforemachining the insulating material 100.

When two openings R1 and R2 are simultaneously subjected to the blastingprocess, the circuit hole H that partially penetrates through theinsulating material 100 may be formed at the shallow opening R1, and thevia hole VH that fully penetrates through the insulating material 100,and is formed on the first pad 300, may be formed at the deep openingR2. In an example where the insulating material 100 includes a fiberreinforcement material 110, the circuit hole H and the via hole VH maypenetrate through the fiber reinforcement material 110.

The metal foil M and the insulating material 100 may be abraded by theabrasives AB propelled against the shallow opening R1 only after theremaining resist R is abraded, a depth of the circuit hole H is smallerthan a depth of the via hole VH. In addition, since a width of the deepopening R2 is larger than a width of the shallow opening R1, circulationof abrasives AB propelled against the deep opening R2 may be moreactively performed in comparison to circulation of abrasives ABpropelled against the shallow opening R1, such that abrasion is rapidlyperformed. As a result, the depth of the circuit hole H is smaller thanthe depth of the via hole VH.

Referring to FIGS. 10A and 10B, the resist R is removed after themachining of the circuit hole H and the via hole VH is completed. Asillustrated in FIG. 10A, an inner surface of each of the circuit hole Hand the via hole VH may be formed to be straight in each of verticalcross sections of the circuit hole H and the via hole VH. Alternatively,as illustrated in FIG. 10B, an inner surface of each of the circuit holeH and the via hole VH may be a concavely curved (U-letter shape) surfaceso that the inner surface of each of the circuit hole H and the via holeVH may be curved in each of vertical cross sections of the circuit holeH and the via hole VH.

Referring to FIG. 10A, in an example, the via hole VH may not penetratethrough the first pad 300. However, referring to FIG. 10B, in anotherexample, the via hole VH may penetrate through the first pad 300, and anupper surface of the first pad 300 may include a concavely (U-lettershape) curved surface as illustrated in FIG. 10B.

Referring to FIG. 11, an electroless plating layer S may be continuouslyformed on the inner surfaces of the circuit hole H and the via hole VH,and on an upper surface of the metal foil M. The electroless platinglayer S may be formed by an electroless plating method, and may be grownfrom a catalyzed surface. A thickness of the electroless plating layer Smay be 5 μm or less.

Referring to FIG. 12, a second resist R′ may be formed on the metal foilM, a plurality of opening regions RO may be formed in the second resistR′, and the plurality of opening regions RO may be disposed on thecircuit hole H or the via hole VH. Since the opening region RO on thecircuit hole H has a width that is smaller than the width of the circuithole H, the second resist R′ covers an edge of the circuit hole H,whereas since the opening region RO on the via hole VH has a widthlarger than the width of the via hole VH, the second resist R′ does notcover the via hole VH.

Referring to FIG. 13, an electroplating layer P may be formed in thecircuit hole H, the via hole VH, and the opening region RO. Theelectroplating layer P may be formed by an electroplating method.According to the electroplating method, the electroplating layer P maybe grown from the electroless plating layer S in an electrolyte.

Referring to FIG. 14, the second resist R′ is removed.

Referring to FIG. 15, the metal foil M and the electroless plating layerS are partially removed, respectively. The metal foil M and theelectroless plating layer S may be removed by etching. As a result, theprinted circuit board according to the example may be manufactured.

FIGS. 16 to 19 illustrate a method for manufacturing a printed circuitboard according to another example. FIG. 16 may be understood asillustrating a step following the step previously illustrated in FIG.11.

Referring to FIG. 16, a second resist R″ is formed on the metal foil M,a plurality of opening regions RO is formed in the second resist R′, andthe plurality of opening regions RO may be disposed on the circuit holeH or the via hole VH. The opening region RO on the circuit hole H has awidth larger than the width of the circuit hole H. The opening region ROon the via hole VH may have a width larger than the width of the viahole VH. That is, the plurality of opening regions RO may be formed sothat the second resist R″ does not cover the circuit hole H and the viahole VH.

Referring to FIG. 17, an electroplating layer P may be formed in thecircuit hole H, the via hole VH, and the opening region RO.

Referring to FIG. 18, the second resist R″ is removed.

Referring to FIG. 19, the metal foil M and the electroless plating layerS are partially removed, respectively. The metal foil M and theelectroless plating layer S may be removed by etching. As a result, theprinted circuit board according to the example may be manufactured.

FIGS. 20 to 23 illustrate a method for manufacturing the printed circuitboard according to an example. FIG. 20 may be understood as illustratinga step following the step illustrated in FIG. 11.

Referring to FIG. 20, a third resist R′″ is formed on the metal foil M,a plurality of opening regions RO may be formed in the third resist R′″,and the plurality of opening regions RO may be disposed on the circuithole H or the via hole VH. The plurality of opening regions RO may beformed so that the third resist R′″ does not cover the circuit hole Hand the via hole VH.

In detail, the opening region RO on the circuit hole H may have a widthlarger than the width of the circuit hole H. It should be noted that adifference between the width of the circuit hole H and the width of theopening region RO may be the same as a thickness of the electrolessplating layer S. The opening region RO on the via hole VH may have awidth larger than the width of the via hole VH. The difference betweenthe width of the circuit hole H and the width of the opening region ROmay be equal to or larger than the thickness of the electroless platinglayer S.

Referring to FIG. 21, an electroplating layer P may be formed in thecircuit hole H, the via hole VH, and the opening region RO.

Referring to FIG. 22, the third resist R″' is removed.

Referring to FIG. 23, the metal foil M and the electroless plating layerS are partially removed, respectively. The metal foil M and theelectroless plating layer S may be removed by etching. As a result, theprinted circuit board according to the example may be manufactured.

While this disclosure includes specific examples, it will be apparentafter an understanding of the disclosure of this application thatvarious changes in form and details may be made in these exampleswithout departing from the spirit and scope of the claims and theirequivalents. The examples described herein are to be considered in adescriptive sense only, and not for purposes of limitation. Descriptionsof features or aspects in each example are to be considered as beingapplicable to similar features or aspects in other examples. Suitableresults may be achieved if the described techniques are performed in adifferent order, and/or if components in a described system,architecture, device, or circuit are combined in a different manner,and/or replaced or supplemented by other components or theirequivalents. Therefore, the scope of the disclosure is defined not bythe detailed description, but by the claims and their equivalents, andall variations within the scope of the claims and their equivalents areto be construed as being included in the disclosure.

What is claimed is:
 1. A printed circuit board comprising: an insulatingmaterial; and a circuit comprising a first region that partiallypenetrates the insulating material, and a second region formed on thefirst region and that protrudes from an upper portion of the insulatingmaterial, wherein the first region comprises a first electroplatinglayer and a first electroless plating layer that is formed between theinsulating material and the first electroplating layer.
 2. The printedcircuit board of claim 1, wherein a width of the first region is largerthan a width of the second region.
 3. The printed circuit board of claim2, wherein the second region comprises a second electroplating layerformed integrally with the first electroplating layer on an uppersurface of the first electroplating layer.
 4. The printed circuit boardof claim 3, wherein a width of the second electroplating layer issmaller than a width of the first electroplating layer.
 5. The printedcircuit board of claim 1, wherein a width of the first region is smallerthan a width of the second region.
 6. The printed circuit board of claim5, wherein the second region comprises a second electroplating layerformed integrally with the first electroplating layer on an uppersurface of the first electroplating layer, a metal foil disposed along acircumference of a part of an outer portion of the second electroplatinglayer, and formed on an upper surface of the insulating material, and asecond electroless plating layer formed between the secondelectroplating layer and the metal foil, and further formed in anintegral manner with the first electroless plating layer.
 7. The printedcircuit board of claim 1, wherein a width of the first region is thesame as a width of the second region.
 8. The printed circuit board ofclaim 7, wherein the second region comprises a second electroplatinglayer formed in an integral manner with the first electroplating layeron an upper surface of the first electroplating layer, and a secondelectroless plating layer disposed along a circumference of a part of anouter portion of the second electroplating layer, and formed in anintegral manner with the first electroless plating layer.
 9. The printedcircuit board of claim 8, wherein a height of the second electroplatinglayer is larger than a height of the second electroless plating layer.10. The printed circuit board of claim 1, wherein a boundary surfacebetween the first region and the insulating material is a concavelycurved surface.
 11. The printed circuit board of claim 1, furthercomprising: a first pad formed in a lower surface of the insulatingmaterial; a via hole formed on the first pad, and configured topenetrate the insulating material; a via formed in the via hole; and asecond pad formed on an upper surface of the via.
 12. The printedcircuit board of claim 11, wherein a thickness of the via is larger thana thickness of the first region, and a thickness of the second region isthe same as a thickness of the second pad.
 13. The printed circuit boardof claim 11, wherein the first region is connected to the via, and thesecond region is connected to the second pad.
 14. The printed circuitboard of claim 11, wherein the via comprises a third electroless platinglayer formed on an inner surface of the via hole and an upper surface ofthe first pad, and a third electroplating layer formed on the thirdelectroless plating layer.
 15. The printed circuit board of claim 14,wherein the second pad comprises a fourth electroplating layer formed inan integral manner with the third electroplating layer on an uppersurface of the third electroplating layer, a metal foil disposed along acircumference of a part of an outer portion of the third electroplatinglayer and further formed on an upper surface of the insulating material,and a fourth electroless plating layer formed between the thirdelectroplating layer and the metal foil and further formed in anintegral manner with the third electroless plating layer.
 16. Theprinted circuit board of claim 11, wherein the via hole has a concavelycurved surface.
 17. The printed circuit board of claim 11, wherein thevia hole penetrates an upper portion of the first pad.
 18. A method ofmanufacturing a printed circuit board, the method comprising: forming aflexible insulating layer; and forming a circuit comprising a firstregion that partially penetrates the flexible insulating layer, and asecond region formed on the first region and that protrudes from anupper portion of the flexible insulating layer, wherein the first regioncomprises a first electroplating layer and a first electroless platinglayer that are formed between the flexible insulating layer and thefirst electroplating layer.